Kilwa became important as a prosperous trading and commercial centre that connected the Indian Ocean littoral to Africa’s interior. Kilwa traded in items as diverse as Arabian crockery, Persian earthenware and Chinese porcelain. Kilwa has been habited since the beginning of the 9th century and reached its commercial peak in the 13th and 14th century.

Between 1331-1332, the great traveller, Ibn Battouta, made a stop here and described Kilwa as one of the most beautiful cities of the known world. Kilwa Kiswani became an important town due to its control of the gold trade from Sofala in Mozambique. Sofala gained its independence from Kilwa in the early 15th century and the Portuguese explorer; Vasco de Gama destroyed Kilwa in 1502, hoping to gain commercial and maritime dominance in the Indian Ocean for the Portuguese. Kilwa Kiswani then grew rapidly, like Zanzibar did at the time due to the slave trade and in the late 18th century came under the control of the Sultan of Oman.

The ruins found on the island now include the vestiges of the great mosque, constructed in the 12th century of coral clay, the remains of the palace built by Sultan Al Hasan in 1310 and numerous smaller mosques from the 12th and 14th century. From the Portuguese era the ruins of a fortress and an entire urban complex with houses and public areas remain. The archaeological artefacts found at the site bare testimony to the commercial and consequently cultural exchanges of which Kilwa was the theatre.

Kilwa Kiswani and the neighbouring ruins of Songo Mnara are two archaeological sites of prime importance to the understanding of the Swahili culture and the Islamization of the east coast of Africa. It was for these reasons that the ruins were awarded UNESCO World Heritage Site status in 1981. They have since been ignored until a joint French / Japanese company are began restoration and exploration work on the ruins in 2003 and in the near future are hoping to open a museum showing the artefacts found in the ruins.

Kilwa Kiswani is now just a small village but the town of Kilwa Masoko is developing in to an important area for tourism in Southern Tanzania. Kilwa Masoko offers tourist deserted palm fringed beaches with safe swimming.